Does gastric sleeve surgery cause vitamin D deficiency?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 30, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Gastric sleeve surgery can contribute to vitamin D deficiency, though it doesn't always cause it. After gastric sleeve surgery, patients have a reduced stomach size and may experience decreased absorption of fat-soluble vitamins like vitamin D. Additionally, patients often consume less food overall, which can limit dietary vitamin D intake. To prevent deficiency, most bariatric surgery programs recommend daily vitamin D supplementation of at least 2,000 IU, as suggested by the most recent study 1. Regular blood tests to monitor vitamin D levels are important, typically at 3,6, and 12 months post-surgery, then annually. Symptoms of vitamin D deficiency include fatigue, bone pain, muscle weakness, and mood changes. Vitamin D is essential for calcium absorption and bone health, and deficiency can lead to osteoporosis and other complications if left untreated. Some key points to consider:

  • The prevalence of vitamin D insufficiency before bariatric surgery is high, with 85% of patients having 25(OH)D levels < 30 ng/mL 1.
  • Postoperative vitamin D supplementation is crucial to prevent further reductions in 25(OH)D levels, especially in patients undergoing malabsorptive procedures 1.
  • High-dose vitamin D supplementation (≥ 2,000 IU daily) is more effective in reducing the occurrence of postoperative hypovitaminosis D compared to lower doses [< 2,000 IU daily] 1. Most patients can maintain adequate vitamin D levels with proper supplementation and follow-up care after gastric sleeve surgery.

From the Research

Vitamin D Deficiency and Gastric Sleeve Surgery

  • Gastric sleeve surgery can lead to vitamin D deficiency due to reduced food intake and malabsorption of fat-soluble vitamins, including vitamin D 2.
  • A study found that vitamin D deficiency was common in patients undergoing bariatric surgery, including gastric sleeve surgery, with a prevalence of over 50% [<50 nmol/L] 2.
  • However, daily supplementation with 2,000 IU of vitamin D3 and 1,500 mg calcium citrate can significantly increase 25(OH)D concentrations and reduce the percent of women who are vitamin D deficient 3.
  • Another study found that vitamin D deficiency and insufficiency were prevalent pre-surgery and reduced significantly with routine supplementation post-surgery, with no significant differences between gastric bypass and sleeve gastrectomy procedures 4.

Risk Factors and Prevention

  • Obesity is associated with chronic inflammation, which may contribute to adverse surgical outcomes, and vitamin D deficiency can further increase this risk 2.
  • Determining the vitamin D status of bariatric surgery candidates and amending it preoperatively may prove greatly beneficial acutely and lifelong 2.
  • Supplementation with additional specific nutrients, including vitamin D, is often needed to prevent deficiency after gastric bypass surgery 5.

Post-Surgical Vitamin D Status

  • A study found that vitamin D levels increased significantly after bariatric surgery, with a mean increase of 8 ng/mL, and the percentage of patients with vitamin D deficiency decreased from 60.6% preoperatively to 26.1% after 3 months 3.
  • Another study found that vitamin D deficiency and insufficiency were reduced significantly with routine supplementation post-surgery, with 8.9% and 26.7% of patients having deficiency and insufficiency, respectively, at 12 months 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.